Lesson 1: Basics for Understanding & Working with VFDs

Topics:

Variable Frequency Drives; Becoming a Better Qualified Person when Working on VFDs; What is a Variable Frequency Drive; Basics for Understanding and Working with VFDs; Understanding Loads; Types of Torque; Other Load Considerations; Typical VFD Applications

Learning Objectives:

– Describe how a VFD operates.
– Identify the components of a VFD.
– Recognize the various torque demands on a VFD.
– Name typical VFD applications.

Lesson 2: Motors for VFDs

Topics:

Basics of Motors; Induction Motor Rotation Basics; Three-Phase Motor Operation; Motor Speed and Number of Poles; Volts/Hz Ratio; Motor Nameplate Information; Recommended Maximum Insulation Temperature; The Inverter Duty Rated Motor

Learning Objectives:

– Explain the theory of AC motor operation.
– Understand the importance of Volts/Hz ratio.
– Describe the information on a motor nameplate.
– Recognize the importance of an inverter duty rated motor.

Lesson 3: VFD Data Input

Topics:

Programming a VFD

Learning Objectives:

– Identify the components on a VFD keypad.
– Enter Motor Nameplate Data into a VFD.
– View the VFD parameters on the keypad display.

Lesson 4: Measurement and Safety for VFDs

Topics:

Safety and VFDs; Test Equipment for VFDs; Making Safe Measurements

Learning Objectives:

– Identify OSHA safety standards.
– Use meters safely.
– Establish an electrical safe work condition.
– Choose the correct meter for troubleshooting VFDs.

Lesson 5: Hands-On Drive Exercises

Topics:

Drive External Accessories; Drive Exercises

Learning Objectives:

– Review a schematic diagram for external VFD accessories.
– Connect indicator lights to an internal drive relay.
– Connect inputs for various desired control functions.
– Check the fault code register to determine the history of faults.

Lesson 6: Electronics for VFDs

Topics:

3-Phase Rectification: The VFD “Front End”; Values Along the Sine Wave; The Diode Symbol; Checking Solid State Components in the Field; Full-Wave Bridge Rectifier; Ripple Voltage and Filtering; Types of Drives

Learning Objectives:

– Understand how an AC sine wave is generated.
– Explain the process of rectification.
– Identify semiconductor components.
– Describe pulse width modulation.
– Recognize basic drive types.

Lesson 7: Sizing and Selecting VFDs

Topics:

Steps for Selecting a VFD; Sizing and Selecting VFDs; Key VFD Specs; Special Considerations

Learning Objectives:

– Create an equipment profile.
– Prepare a detailed analysis of performance requirements.
– Research either machine or process equipment history.
– Identify environmental conditions.
– Analyze the power distribution system.

Lesson 8: Installation and Startup of VFDs

Topics:

Steps to Selecting a VFD; VFD Installation Requirements; Startup

Learning Objectives:

– Develop a checklist of items.
– Comply with manufacturer’s instructions and specifications.
– Identify with National Electrical Code® requirements.
– Verify proper overcurrent protection to drive.

 Lesson 9: Troubleshooting VFD Systems and Motors

Topics:

Troubleshooting 3 Phase Motors; Insulation Considerations for VFD Motors; Solutions Used to Prevent Motor Failures; Motor Bearing Issues for VFDs; Bearings; Resolving Bearing Problems; Troubleshooting VFDs; VFD Faults;

Learning Objectives:

– Troubleshoot three-phase motors.
– Identify motor failures.
– Discuss the six conditions needed to troubleshoot VFDs.
– Discuss a by-pass option.

Lesson 10: Preventative Maintenance

Topics:

Preventive Maintenance: NETA Recommendations

Learning Objectives:

– Conduct a visual and mechanical inspection of the VFD.
– Perform electrical testing.
– Test the equipment grounding path.